This drawing depicts a type of phytoplankton known as a diatom.
Diatoms are found in oceans all over the world, but they are particularly plentiful in Antarctic waters. Diatoms "bloom" at the ocean surface during the Antarctic spring and summer (November-March).
Phytoplankton are eaten by tiny marine animals, particularly krill. And what do phytoplankton eat? They make their own food through photosynthesis. Fueled by the energy of sunlight, they convert carbon dioxide and water into a simply, sugary food. During photosynthesis, phytoplankton release oxygen--vital for us humans to live--as a waste product! They also take up carbon dioxide, released into the atmosphere by automobiles and industry. Some scientists believe that too much carbon dioxide in the atmosphere may cause the Earth to get too hot (global warming).
Tiny as they are, phytoplankton perform a huge service for our Earth. They provide food for marine life, oxygen for human life, and reduce the amount of carbon dioxide in Earth's atmosphere.
Sources:
Drawing by Ted Williams, Artist, UT Publications Center